Different users have different heights and body shapes. When a normal table or a desk is used, if its table plate may be adjusted to a proper height, users may feel more comfortable when using the table or the desk. Therefore, there are several adjustable mechanisms disposed on a table or a desk for automatically adjusting a table plate or the height of a table plate for users of different heights and body shapes.
Currently, tables with height adjusting function mainly use mechanisms like a pneumatic cylinder lifting structure, a hydraulic actuating cylinder lifting structure, a screw thread lifting structure, a gear wheel lifting structure, or a lever lifting structure to adjust the height of a table plate. However, no matter what type of adjusting mechanism is used, when adjusting the height or a horizontal position of a table plate, users often lose sight of noticing whether there is an obstacle staying below or above the table plate. Therefore, it is often to occur that a table plate hits an obstacle below or above the table plate, causing the table plate tilted and causing objects on the table plate fallen, damages of an adjusting mechanism or the obstacle.